Atletico Madrid say they are owed a further €80-million for Antoine Griezmann.
Barcelona have confirmed the signing of the French international forward having paid €120-million to meet his release clause.
However, Atletico say they want €200-million as it was clear Griezmann and Barca had reached a deal before his release clause was slashed by €80-million.
"Antoine Griezmann, represented by his lawyer, has appeared at the headquarters of the Professional Football League to unilaterally terminate the contract that binds the player with Atlético de Madrid, having deposited on behalf of the player the amount of €120m from Fútbol Club Barcelona," read the statement.
"Atlético de Madrid believes that the amount deposited is insufficient to meet its release clause since it is obvious that the commitment of the player and the Football Club Barcelona was closed before the aforementioned clause was reduced from €200m to €120m.
"It was also prior to the date on which the clause was modified the communication that the player made on May 14 announcing his disengagement from the club.
"Atlético de Madrid believes that the termination of the contract occurred before the end of last season due to events, acts and demonstrations carried out by the player and that is why we have already started the procedures we consider appropriate for the defence of our rights."
Griezmann's agreed a five-year deal at the Camp Nou with Barceloa setting his release clause at 800-million Euro.